The present invention relates to a piece of furniture with a movable furniture component (in particular, a drawer or door), a drive unit (in particular, electric), and a device for the mechanical transmission of force from the drive unit to the movable furniture component or the body of the piece of furniture. In particular, a pin is arranged on a lever which can be powered by the drive unit, for the ejection and/or insertion of the movable furniture component. The device is arranged in a guide track for the transmission of tensile and thrust forces.
Devices with which the movable furniture component can be ejected via a lever are used, in particular, in a piece of furniture with movable furniture components that, for reasons of design or for practical reasons, have no handles. The manual opening of such a furniture door or drawer is made possible for a user only after the powered opening of the movable furniture component over a first distance to form a gripping gap between the movable furniture component and the body of the furniture. Spring-loaded mechanisms (touch-latch) or drawers driven by an electric motor are known, for example.
For example, a cupboard with several handle-less drawers is disclosed in U.S. Pat. No. 5,158,347, in which the drawer to be opened can be selected by entering a code and can then be partly withdrawn from the cupboard via a pin, attached to the drawer, off which a powered eccentric rolls. The problem here, among other things, is that the opening process is designed differently for drawers filled to different extents.
A drawer with a certain minimum contents weight rests against the eccentric with the pin arranged on it over the entire acceleration distance provided and is thus accelerated by it in the proposed manner. A drawer below this minimum weight will already undergo such a great acceleration after covering part of the overall provided acceleration distance that the pin lifts off from the eccentric and the drawer moves unpowered, under the influence of the frictional forces only. Through the friction-induced dissipation of the kinetic energy, the drawer then reduces its speed until the pin arranged on it again comes into contact with the powered eccentric, as a result of which the drawer is accelerated again. This results overall in an uneven, sputtering acceleration of the drawer. This is not only undesirable for reasons of user acceptance, but also accelerates the wear of the mechanical components of the piece of furniture and the drawer.
In addition, the state of the art described in U.S. Pat. No. 5,158,347 has the disadvantage that, with the device shown there, it is not possible to insert the opened drawer into its closed end-position. In order to perform this function, an additional automatic insertion mechanism would thus have to be provided, which is disadvantageous both for cost reasons and because of the associated additional design outlay and the increased space requirement.
The arrangement of the device for the transmission of force in a guide track is disclosed in U.S. Pat. No. 3,862,788. This has among others the advantage that during the ejection of the movable furniture component, an interruption of the contact between the device for the mechanical transmission of force and the movable furniture component is prevented. A further advantage is that with such a device, the insertion of the movable furniture component at a distance positioned in front of the closed end-position of the movable furniture component with the device used for ejection is also made possible.
However the problem here is that the length of the lever shown in U.S. Pat. No. 3,862,788 for the mechanical transmission of force must be chosen for each movable furniture component according to the distance between the closed and the open end-positions.